Fuse device



y 1944- A. G. STEINMAYER ETAL, ,347,851

FUSE DEVICES Filed July 20, 1940 R m N E V W.

ATTORNEY.

Patented May 2, 1944 UNITED STATES PA NT OFFICE F USE DEVICE Alwin G. Steinmayer, Milwaukee, and William O. Schultz, South Milwaukee, Wis., assignora to Line Material Company, Milwaukee, Wis, a corporation of Delaware Application July 20, 1940, Serial No. 346,572

2 Claims.

Iii

obtain a proper contact between the fuse link and thesupporting structure, and it is further difficult to re-fuse the device in a comparatively quick and easy manner.

Therefore, it is an object of this invention to provide for an electrical transmission line a fuse device comprising a pair of spaced conductor arms, each of which is provided with a link holding means whereby a fuse link may be received therein with comparatively no arcing during ener ized circuit installation.

More particularly, it is an object to provide for a fuse device a fuse link comprising a contact immediately adjacent an insulating tube whereby the link may be installed in the fuse device under energized circuit conditions by -inserting the tube portion of the link in the link holding means and then allowing the link to be snapped into circuit making position, thereby preventing any burning and pitting of the contact parts.

Another object is to provide a fuse mounting which is adapted to receive a fuse link having a biasing means whereby, when installed in the mounting, the link is under proper tension.

A further object is to provide a fuse device having a pair of conductor arms each provided with a non-gripping, wedge-like link holding means adapted to hold a fuse link in a predetermined position relative to the holding means, whereby upon rupture of the link the ruptured parts are released from the device, thereby providing a fuse device which is refuseable in a quick and simple manner.

In the drawing:

Fig. l is a view in side elevation showing the embodiment of my invention.

Fig. 2 is an enlarged view taken on the lines 2-2 of Fig. l with the link assembly removed.

Fig. Bis an enlarged view taken on the lines 3-3 of Fig. 1 with the link assembly removed. Fig. 4 is an enlarged view, partly in section, of the fuse link assembly shown in Fig. 1.

Like parts are designated by the same reference numerals throughout the several views.

(Cl. Milk-1M) In Fig. 1 an elongated cylindrical insulator support i is provided with terminal members 2 and 3 mounted thereon by means of the bolts 4 which extend through the insulator i and are secured thereon by nuts 5 drawn tightly against the washers t.

Extending in parallel relation to the insulator l are conducting portions 71 which are integral portions of the terminals 2 and 3. Mounted on the portions ii are connector elements ii and t commonly used and adapted to receive electrical conductors (not shown) for connection with theterminals.

As indicated, the support 5 is provided intermediate its ends with a hanger it, shown iragmentarily, clamped to the support by means of the strap il,bolts l3,and nuts iii.

Numeral l6 designates generally a rigid conductor member or arm mounted upon the terminal 22 and comprising a casting having a boltreceiving base iii secured to the terminal 2 by means oi the bolt i. A pair of spaced apart lugs 06 project rearwardly from the base it; and engage opposite sides of the conducting portion l, thereby holding the arm id in a non-rotative position relative to the terminal 2. The conducting arm is provided at its outer end with a slightly upturned contact head designated gcnerally by the numeral ii.

The head l'i, shown enlarged in Fig. 2, comprises a pair of arcuate side members it extending outwardly and terminating in a pair of spaced apart diverging guides 09 which form a fuse link passageway Ell extending into the opening it formed by the side members iii. An arcuately curved contact surface is provided at 22, tapering as shown to form a wedge or cone-like seat for a fuse link conical contact more fully described hereinafter.

A pivotally movable rigid conductor arm, designated generally by the numeral 23, comprises a casting having at one end a pair of spaced apart pivot legs 23A (one being shown), each having a lug or stop means 26; and at the other end a cone-like contact head, designated generally by the numeral 28.

The head 28, shown enlarged in Fig. 3, comprises a wedge or cone-like seat 21! having a guide portion 28 extending rearwardly and outwardly relative to the arm 23 forming the [use link passageway 29.

The conductor arm 23 is pivotally mounted in a terminal housing designated generally by the numeral 30, integral with the terminal 3, and comprising side walls 3| (one being shown) a top by any convenient means, as by a wedge, thereby increasing the diameter of the bearing at this point and preventing passage through the apertures 34.

A flat spring 24 having a curved contact head 24A is mounted on the housing 30 and secured to the top 32 by means of a bolt 248. The spring 24 functions as a biasing means for urging the conductor arm 23 away from the upper conductor arm i4, as hereinafter more fully described.

The fuse mounting hereinabove described is provided with a fuse link assembly A. The assembly shown in detail in Fig. L comprises a strain wire 31 secured at its upper end by solder 33 to a mounting ring 33 formed from a comparatively stiff wire 40. A stiff metal tube 4| flanged at 42 is mounted over the strain wire 31 and provided at the flanged end with a frusto-conical contact 43. Th parts are secured as a rigid assembly to the ring 33 by the solder 33. The frusto-conical contact is tapered at 44 to provide a complementative contact surface for the cone-like seat 22 on the head H.

A current-responsive means or fusible wire 45 is secured to the lower end of the metal tube 4! at 48 by any convenient means as solder. The lower ends of the strain wire 31 and fusible wire 45 which extend a predetermined distance below the lower end of the metal tube 4! are secured to a flexible conductor 41 at 43 by solder.

A comparatively light insulating tubular member 43 is mounted on the tube 4! in a tight-fltting relationship. The upper end of the member 49 abuts the contact 43 and its lower end extends a short distance below the solder joint 43, thereby protecting the fusible section against damage through handling. The lower end of the member 43 is anchored in relative position with the flexible conductor 41 by flattening the flanged tube 50 on the conductor 41.

Before the tube In is flattened, however, a spring 3| having a predetermined tension under predetermined conditions is mounted on the con; ductor 41 with its upper end 32 projecting into the tube Iii. When the tube 33 is flattened, the upper end of the spring is held in fixed position relative to the flexible conductor 41.

A length of the conductor 41 is coiled within the spring BI and the lower end 33 of the spring ii is anchored to the conductor by a collar 34 which is flattened into locked contact with the conductor. 1

The lower end of the conductor 41 is provided with a frusto-ccnical contact 33 having an aperture 34 through which the conductor 41 passes to form a loop 51 on the opposite side of the contact as shown. The conductor 41 and contact I II are secured in rigid relationship with each other by solder II. The loop 31 is tinned with solder to stiffen it as a ring.

The link assembly A is operatively engaged with the fuse mounting shown in Fig. 1 by insertcontact head 28, through the opening 28. It may be noted that the guide portion 28 facilitates installation of the link at this point of the fusing operation and that the arm 23 is in the position shown by the broken lines, thereby positioning the contact head 23 where it may readily receive the contact ll,

As the assembly is moved upwardly, the arm 23 is moved into the position shown in Fig. l where it makes positive electrical contact with the edge 33, which edge also holds the arm against further upward movement. At this point it is to be noted that the spring head 24!. is moved upwardly by the arm 23, thereby flexing the spring 24. The flexed spring 24 tends to urge the arm 23 downwardly away from the upper conductor arm i4. It is also to be noted that a high pressure contact is made between the edge 33 and the arm 23 due to the lever advantage between the edge 33 and the contact head 20 about the pivot 33. The assembly is moved upwardly away from the contact head i1 until it is in a position where the assembly may be moved inwardly toward the contact head i1 and located in the opening 2| as shown by the broken lines.

It may be noted at this point of the installation that the energized parts of the device are insulated from each other by the tube 49, thereby preventing arcing during installation. The circuit is closed by withdrawing the prong end or the hot-line stick from the ring 33, thereby allowing the contact 43 to be snapped into positive electrical relationship with the contact head 11 by reason of the biasing action of the spring 5! which holds the link in proper tensioning relationship between the contact heads i1 and 26.

It may be noted that it is comparatively easy for anoperator to quickly and properly mount the fuse link between the heads l1 and 26 because of the directional location of the passageways 20 and 23, and because of the predetermined wedge-like seating contact made by the contacts 43 and 83 with the cone-like seats 22 and 21 respectively.

It may be further noted that since the i'use mounting is not provided with a predetermined ing the prong end of a standard hot-line stick (not shown) in the ring 33. The link is guided by means of the stick to permit the lower end of the conductor 41 to pass into position with the biasing ,means it is adapted to receive and properly hold any one of a number of differentially rated fuse links having 'a predetermined biasing means attached thereto.

It may also be noted that a comparatively large contact area is made between the terminal ends of the fuse link and the contact heads i1 and 23, thereby providing high current carrying contacts which prevent overheating at relatively high currents.

When an overload condition occurs in the circuit including the fuse device, the fusible section is ruptured by the melting of the fuse wire 43 and strain wire 31. The lower ends of the ruptured wires are snapped from within the tube 43 by the tensioned spring 5i, whereupon the lower portion of the link drops out of contact with the head 23 and the arm 23 pivots by reason of gravity into its prefused position shown by the broken lines.

The upper end of the ruptured fuse link is blown free of the contact head H by the expanding gases resulting from the melted wires. The device is now in condition to be re-fused.

It is apparent from the foregoing description that the objects of this invention have been accomplished by providing a fuse device having a pair of conductor arms, each being provided with II a fuse-link holding means adapted to provide quick, positive, simple, and comparatively arcless installation of a fuse link.

It it further apparent that a fuse mounting has been provided which is adapted to receive a fuse link having a biasing means whereby the link when installed in the mounting is held under a proper tension.'

We claim:

l. A fuse cutout comprising: a first fixed terminal, a second fixed terminal spaced from said first terminal, said first terminal including means for detachably anchoring and effecting electrical contact with one terminal of the hereinafter-recited fuse-link, a rigid elongate arm pivotally connected at one end only to said second terminal, said arm having a free end remote from said second terminal and including means for detachably anchoring and efiecting electrical contact with the other terminal of said fuse-link, said second terminal including positive stop means for definitely limiting the movement of said arm about its pivotal center toward said first terminal, said stop means being operative to establish a firm electrical contact between said second terminal and said arm, and a fuse-link interconnecting and supported by said first terminal and the free end of said arm, conjointly, said fuse-link including a fusible section and a tension spring, the latter being normally operative to hold said arm in contact with said stop means while at the same time applying tension to said fusible section.

2. A fuse cutout comprising: a first fixed terminal, a second fixed terminal spaced from said first terminal, said first terminal including means for detachably anchoring and effecting electrical contact with one terminal of the hereinafter-recited fuse-link, a rigid elongate arm pivotally connected at one end only to said second terminal, said arm having a free end remote from said second terminal and including means for detachably anchoring and effecting electrical contact with the other terminal of said fuse-link, said second terminal including positive stop means for definitely limiting the movement of said arm about its pivotal center toward said first terminal, said stop meansbeing operative to establish a firm electrical contact between said second terminal and said arm, a second positive stop means for definitely limiting the movement of said arm about its pivotal center away from said first terminal, said second stop means being operative to hold said arm in a position wherein a fuse-link can conveniently be attached to its free end when re-fusing the cutout, and a fuse-link interconnecting and supported by said first terminal and the free end of said arm, conjointly, said fuse-link including a fusible section and a tension spring, the latter being normally operative to hold said arm in contact with said first-mentioned stop while at the same time applying a predetermined ten sion to said fusible section.

ALWIN G. STEINMAYER. WILLIAM O. SCHULTZ. 

